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Gene

TWNK

twinkle mtDNA helicase

Summary

Cytogenetic location
10q24.31
Coordinates
Chromosome 10: 100,987,543–100,994,403 (GRCh38)
Exons
5 exons across 6.9 kb
Protein
684 amino acids
Inheritance
Autosomal recessive
Also known as
PEO, PEO1, TWINKLE, FLJ21832, TWINL
Previous symbols
IOSCA, C10orf2
MANE Select transcript
ENST00000311916.8NM_021830.5
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated reports relevant to this gene

  • Female Infertility

    • Diminished or absent ability of a female to achieve conception.

      • ClinGen rates the link definitive
      • 2 GenCC submitters rate it definitive or strong

  • Primary Mitochondrial Disease

    • Progressive External Ophthalmoplegia with Mitochondrial DNA Deletions

      Caused by variants in nuclear genes such as POLG, TWNK, SLC25A4 and RRM2B that lead to multiple mitochondrial DNA deletions, causing drooping eyelids, weak eye movements and muscle weakness, usually in adulthood.

      • 2 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing guides monitoring of eye, heart and swallowing function and avoidance of valproate in POLG disease.

    • Mitochondrial DNA Depletion Syndrome

      Caused by variants in nuclear genes such as POLG, TWNK, TK2, DGUOK, MPV17, RRM2B and SUCLA2, which reduce the amount of mitochondrial DNA and can cause muscle, liver or brain disease.

      • 2 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing is directly actionable: valproate must be avoided in POLG disease because of the risk of fatal liver failure, and TK2 deficiency has a nucleoside therapy.

Broader groupings

  • Autosomal Recessive Cerebellar Ataxias (incl. CANVAS and AVED)

    • Autosomal Recessive Cerebellar AtaxiaAutosomal recessive

      One of 57 genes linked to it

      A group of recessively inherited ataxias caused by biallelic variants in genes such as RFC1, FXN, SACS, TTPA, SETX, APTX, PNKP, ANO10 and SYNE1.

      • 2 GenCC submitters rate it definitive or strong
      What knowing changes

      Ataxia with vitamin E deficiency (TTPA) is treatable with vitamin E supplements; other forms are managed with physiotherapy and symptom care, and relatives can be offered carrier testing.

Inheritance

Autosomal recessive
It takes a changed copy from each parent. With one, you are a carrier and usually unaffected; when both parents are carriers, each child has a one-in-four chance of inheriting two.

How TWNK is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
Chromosome 10, with a bracket where TWNK sits. TWNK and 15 genes near it on chromosome 10, from 100,490,973 to 101,490,972.Chromosome 1010q24.31p15.3p15.2p15.1p14p13p12.33p12.32p12.31p12.2p12.1p11.23p11.22p11.21p11.1q11.1q11.21q11.22q11.23q21.1q21.2q21.3q22.1q22.2q22.3q23.1q23.2q23.31q23.32q23.33q24.1q24.2q24.31q24.32q24.33q25.1q25.2q25.3q26.11q26.12q26.13q26.2q26.3100.6 Mb100.8 Mb101 Mb101.2 Mb101.4 MbSEC31B: 100,484,998–100,519,892, reverse strandSEC31B: 100,505,628–100,529,881, reverse strandNDUFB8: 100,523,668–100,530,000, reverse strandNDUFB8HIF1AN: 100,529,072–100,681,896, forward strandHIF1ANPAX2: 100,735,380–100,829,944, forward strandPAX2SLF2: 100,912,963–100,965,134, forward strandSLF2MRPL43: 100,968,131–100,990,450, reverse strandMRPL43SEMA4G: 100,969,493–100,985,871, forward strandSEMA4GTWNK: 100,987,543–100,994,403, forward strandTWNKLZTS2: 100,996,539–101,007,852, forward strandLZTS2PDZD7: 101,007,679–101,032,295, reverse strandSFXN3: 101,031,229–101,041,244, forward strandSFXN3KAZALD1: 101,061,108–101,068,648, forward strandKAZALD1TLX1: 101,131,011–101,137,789, forward strandTLX1LBX1: 101,226,180–101,230,401, reverse strandLBX1BTRC: 101,354,030–101,557,324, forward strandBTRCDiagram of TWNK: 5 exons on the forward strand of chromosome 10Exon 1: 28 known disease-causing sitesExon 2: 12 known disease-causing sitesExon 3: 2 known disease-causing sitesExon 4: 2 known disease-causing sitesExon 5: 1 known disease-causing siteExon 1: 100,987,543–100,989,453, 1,911 basesExon 2: 100,989,644–100,989,884, 241 basesExon 3: 100,990,436–100,990,543, 108 basesExon 4: 100,990,869–100,991,010, 142 basesExon 5: 100,993,190–100,994,403, 1,214 bases123455′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 3.6 kb of the gene's 6.9 kb; 2,055 of those bases code for the protein.

How a genome test reads TWNK

45

positions in TWNK where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 6.9 kb of TWNK, introns included, not only the 3.6 kb of exons.

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). TWNK gene: twinkle mtDNA helicase. Retrieved 17 October 2026, from https://dantelabs.com/genes/twnk

Vancouver

Dante Labs. TWNK gene: twinkle mtDNA helicase [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/twnk

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